There exists a condition of quantum entanglement. Two photons may be "quantum entangled" if produced by the same particle interaction and emerging in opposite directions. They stay quantum entangled even when separated by vast distances (even light-years apart). Two quantum-entangled photons will make identical decisions when forced to choose among two equally probable pathways. They make the same decision at the same instant. If there is some unknown communication path between the two photons, it has been observed to function at least SEVEN TIMES the speed of light.

Another explanation, of course, is that the effect is completely instantaneous.